INTRODUCTION CD4 testing in South Africa is based on an integrated tiered service delivery model that matches testing demand with capacity. The National Health Laboratory Service has predominantly implemented laboratory-based CD4 testing. Coverage gaps, over-/under-capacitation and optimal placement of point-of-care (POC) testing sites need investigation. OBJECTIVES We assessed the impact of ...

This paper considers a class of stochastic resource allocation problems that requires simultaneously determining the customers that a capacitated resource must serve and the stock levels of multiple items that may be used in meeting these customers’ demands. Our model considers a reward (revenue) for serving each assigned customer, a variable cost for allocating each item to the resource, and a...

The covering of a graph with (possibly disjoint) connected subgraphs is fundamental problem in theory. In this paper, we study version to cover graph's vertices by subject lower and upper weight bounds, propose column generation approach dynamically generate feasible promising subgraphs. Our focus on the solution pricing which turns out be variant NP-hard Maximum Weight Connected Subgraph Probl...

We consider the node-capacitated routing problem in an undirected ring network along with its fractional relaxation, the node-capacitated multicommodity flow problem. For the feasibility problem, Farkas’ lemma provides a characterization for general undirected graphs asserting roughly that there exists such a flow if and only if the so-called distance inequality holds for every choice of distan...

In this talk we present a unified Variable Neighborhood Search (VNS) algorithm for the Capacitated Arc Routing Problem (CARP) and some of its variants the Capacitated Arc Routing Problem with Intermediate Facilities (CARPIF) and the Capacitated Arc Routing Problem with Intermediate Facilities and Length restrictions (CLARPIF). Routing problems represent one of the most prominent classes of mode...

In a two-capacitated spanning tree of a complete graph with a distinguished root vertex v, every component of the induced subgraph on V\{v} has at most two vertices. We give a complete, non-redundant characterization of the polytope defined by the convex hull of the incidence vectors of two-capacitated spanning trees. This polytope is the intersection of the spanning tree polytope on the given ...

Many graph problems seek subsets of their vertices that maximize or minimize objective functions on the vertices. Among these are the capacitated p-median problem, the geometric connected dominating set problem, the capacitated k-center problem, and the traveling tourist problem. Prior genetic algorithms research in this area applied a simple mutation of an allele by random replacement. Recentl...

hub covering location problem, network design,   single machine scheduling, genetic algorithm,   shuffled frog leaping algorithm   hub location problems (hlp) are synthetic optimization problems that appears in telecommunication and transportation networks where nodes send and receive commodities (i.e., data transmissions, passengers transportation, express packages, postal deliveries, etc.) th...